Knife sharpener



May 27, 1924. 1,495,329

A.4 KINDELMANN KNIFE SHARPENER Filed OCT.. 28, 1922 54m/baute@ Patented May 27, 1924.

Il' T 0 F l C E KNIFE SHARPE'NER.

Application led October 28, 1922.

To all whom t may concern.'

Be 1t known that I, ALBERT KINDELMANN,

- a citizen of the United States, residing at Floral Park, in the county of Queens and State of New York, have invented certain new and useful Improvements in Knife Sharpeners, of which the following is a specification.

This invention relates to a knife sharpener and, more particularly, to a device for rapidly forming a uniform', sharp cutting edge by scraping the portion of a bladeforming the sides of the cutting edge.

Sharpening devices have been proposedv inv which a pair of tangent discs having tangent or intersecting scraping edges are so supported that. a knife may be drawn across the edges ofthe discs near their point'of intersection and the sides of the blade contacting with the discs may be scraped until they conform to the sharp converging opening between the discs. Devices of this type have not, however, proven satisfactory as they tend to produce a jagged and uneven edge which requires honing or stropping before it is suitable for use. The unevenness of the edges produced in this manner is due primarily to a slight chattering or vibration between the scraping edges of the discs and the knife blade which causes the scraping edges to alternately give slightly and grip the knife blade, thereby forming a series of slight knicks or waves in the knife edge or to produce a saw tooth effect.

An object of the present invention is to provide a knife sharpening device by which a sharp, smooth edge may be rapidly formed on a blade to be sharpened.

Another object of the invention is to provide a knife sharpening device having a rigid supporting means for the sharpening elements which may be easily and cheaply constructed.

With these and other objects in view the invention comprises the device described and set forth in the following specification and claims.

The various features of the invention are illustrated in the accompanying drawing in which:

Fig. 1 is a plan view of a sharpening device embodying a preferred form of the invention,

Fig. 2 is a rear elevation of the device shown in Fig. 1 and a section of a knife blade in position to be sharpened, and,

Serial No. 597,549.

Fig. 3 is a section of the device taken on line 3-3 of Fig. l.

In the present invention the scraping edges of the sharpening device are arranged in a plane positioned atan acute angle of materially less than 90 to the edge of the Iblade being sharpened, an angle of 45o being` preferred. The scraping edges are formed by a pair-of frustro-conical members having their larger flat bases in an inclined plane and having the circular edges of these bases contacting and tangent to each other. The frustro-conical members are suitably supported in this position'by attaching them on an inclinedplate with the largerbases held firmly against the under side ofthe plate by means of screws extending through openings in the plate and into openings in the axes of the scraping or sharpening members. The inclined supporting plate is preferably formed integral with a supporting base by cutting and 'stamping a sheet of metal to the required shape and form. The axial mounting of the sharpening members permits them to be rotated, upon loosening the fastening screws, to bring new portions of the edges into scraping position as the edges become worn with use.

Referring more particularly to the accompanying drawings, a pair of frustro-conical sharpening elements 10 land 112 are mounted on a plate 14 integral with a base plate 16 and extending upwardly from the base plate at an angle of substantially 45. The

sharpening elements 10 and 12 are mounted on the under face ofthe plate 14 by means of short screws 18 and 20 extending through openings 22, illustrated inv dotted linesy in Fig. 3, and into threaded openings 24 eX- tending axially through the sharpening elements. The screws have heads 26 which abut the upper face of the plate 14 as the screws are tightly screwed into the openings 24 and hold the sharpening elements rigidly to the plate.

The elements 10 and 12 are so mounted that their larger flat bases 28 and 30` are adjacent the under side of the plate 14 thereby insuring the placing of the cutting faces or edges of these elements in a single plane regardless of any variations in the size or thickness of the elements. The cuttin or scraping edges of the sharpening inem ers are formed by the edges 32 and 34 between the bases 28 and 30 and the tapered sides of the members, the members being so mounted on the plate 14 as to contact at a tangent point 36. A notch 38 is cut in the plate 14 in the line of the tangent point 36 to permit a knife to be drawn in a horizontal position between the sharpening edges. The sharpening elements are made of a good quality of tool steel, harder than the ordinary type of knives to be sharpened, and the taper of the conical sides is such as to provide a very slight clearance and a strong,

rigid, cutting edge. A taper or inclination of about 5o to the axis of the conical sides is usually suitable for this purpose.

When a knife is to be sharpened it is placed in a horizontal position in the gap 40 between the sharpening members and pressed firmly downwardly toward the tangent point 36 and drawn in the direction indicated by the arrow in Fig. 3. A very thin strip of metal is scraped from each side of the blade, the sides of the blades being thus shaped to lit the shape of the gap. This is repeated when necessary until the edge of the blade reaches the vanishing point corresponding to the meeting of the cutting edges at the tangent point 36 and a very sharp ed e is thereby formed.

y the inclined position of the sharpening edges 82 and 311, an oblique cutting edge is presented to the knife, thus extending the cuttingaction over a short length of the knife blade, thereby lessening the tendency for the blade to vibrate. The inclined position of the plate 1st also tends to distribute the bending or'vibratingaction of the knife on the plate and thus permits the sharpening` elements to be held more rigidly and steadily. A thinner cut into the sides of the knife edge is also provided by the inclined position of the scraping elements and the scraping action does not extend as far up on the blade, thus providing a shorter, stronger edge.

rllhe device may be mounted on a horizon-- tal surface as, for example, a table top orshelf, or on a vertical wall surface. For this iig-casas purpose openings 42 are provided in the base plate 16 through which fastening or attaching screws may be mounted. The base plate 16 is also preferably extended below the sharpening members 10 and 12 as indicated at i4 to provide a guard preventing the knife from cutting the supporting table or surface in case it should slip downwardly after passing the Sharpeners. rlhe form of the supports for the sharpening elements illustrated above may be easily and cheaply formed by stamping from sheet metal in a single stamping operation. lt is to be understood, however, that other forms of supports may be used when desired without departing froml the broader features of the invention.

Having described the invention, what l. claim and desire to secure by Letters Patent is:

1. A device of the kind described which comprises a supporting member having a base plate and an integral plate extending upwardly therefrom at an angle of substantially 45 and a pair of frustro-conical members mounted on said upwardly extending plate with their larger bases against the lower face of said plate and tangent to each other, said upwardly extending plate having a slit for the passage of a blade between said frustro-conical members.

2. A device of the kind described which comprises a supporting member having a base plate and an integral plate extending upwardly therefrom at anV angle of substantially less than a right angle, and a pair of frustro-conical members mounted on said upwardly extending plate with their larger bases against thelower face of said plate and tangent to each other, said upwardly extending plate having a slit for the passage of a blade between said frustro-coniral members.

In testimony whereof l aflix my signature.

ALBERT KNDELMA NN. 

